Pressure relief means



PRES SURE RELIEF MEANS Filed June l2, 1937 Pig. 1

nventor: Harley H. B'xler,

I-lis Attovney.

Patented New. 26, 1940 UNITED sTATs PRE S SURE RELIEF MEANS Harley H. Bixler, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application June l2, 1937, Serial N o. 147,917

Claims.

My invention relates to pressure relief means and more particularly to pressure relief means for use in refrigerating apparatus.

It is an object of my invention to provide an 5 improved pressure relief arrangement for refrigerating machines of the hermetically sealed ltype.

A further object of my invention is to provide an improved pressure relief valve which is of simple construction, which is positive in operation, and which is economical to manufacture.

Further objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to the accompanying drawing in which Fig. 1 is a side elevational View, partly in section, .of a refrigerating machine provided with a pressure relief arrangement embodying my'invention; Fig. 2 is an enlarged sectional view of an exhaust muffler having a pressure relief valve therein included in the refrigerating machine shown in Fig. 1, the pressure relief valve being shown in its initial position of operation; Fig. 3 is a fragmentary sectional View of the exhaust muffler and pressure relief valve shown in Fig. 2, the pressure relief valve being shown in its final position of operation; and Fig. 4 is a fragmentary perspective view, partly in section, of a modified form of the pressure relief valve shown in Figs. 2 and 3.

Referring to the drawing, in Fig. 1 I have shown a refrigerating machine of the household type provided with an hermetically sealed enclosing casing I0 formed of an upper casing section II and a lower casing section I2, the adjacent edges of these casing sections being welded together at I3 over a reinforcing ring I4. The casing sections II and I2 are preferably made of steel and are mounted on a removable y ,5 20 and 2| are arranged within the enclosing casing Il! and communicating respectively with intake and exhaust ports in the compressor I6 through conduits 22 and 23, respectively. The intake and exhaust mufiiers 20 and 2l are provided in order to minimize the transmission of operating noises produced by the compressor I6 to the exterior of the enclosing casing I0. A lubricant reservoir 24 is formed in the lower casing section I2 and contains a body of lubricant therein which is recirculated from the lu- 10 bricant reservoir 24 to the bearings and moving parts vof the compressor I6 and the driving motor I'I during operation of the refrigerating machine. Also, aY quantity of gaseous refrigerant is contained in the upper portion of the enclosing casing I0.

During normal operation of the refrigerating machine illustrated, gaseous refrigerant in the enclosing casing ID is drawn into the compressor I6 through the intake muffler 20 and the conduit 22 and compressed and discharged into the exhaust muffler 2l through the conduit 23. The compressed refrigerant is conducted from the exhaust muffler 2I through a conduit 25 into an air cooled condenser 26 of the natural draft type supported about the enclosing casing ID upon an annulus of fins 26a. The compressed refrigerant in passing through the condenser 26 is cooled and condensed into a liquid and then iiows through a conduit 21 into a suitable floatoperated flow-controlling device 28. Liquid refrigerant is supplied from the float-operated flow-controlling device 28 through a liquid supply conduit 29 to a cooling unit 30. The cooling unit 30 comprises a sheet metal evaporator of the flooded type which is supported from an inner liner 3| of the removable top Wall I5 in a food compartment 32 formed in the refrigerator cabinet cooled by the refrigerating machine. The liquid refrigerant contained in the evaporator 3U is vaporized by the absorption of heat from the food compartment 32 and the vaporized refrigerant is collected in a cylindrical header 33 formed in the evaporator 30 which is normally'maintained about one-half full of liquid refrigerant. The vaporized refrigerant which accumulates above the level of the liquid refrigerant in the header 33 is returned to the interior of the enclosing casing ID through a suction conduit 34 which communicates with the header 33 above the normal liquid level therein. It will be noted that the discharge end l 34a of the suction conduit 34 is located above the normal level of the body of lubricant contained in the lubricant reservoir 24 formed in the lower casing section |2. The vaporized refrigerant returned to the enclosing casing I0 is again drawn into the compressor I6 through the intake muiller 20 and the conduit 22, and the cycle above described is continuously repeated until the food compartment v3i. in which the evaporator 30 is located is cooled to the desired temperature. The conduit 23, the exhaust mufiler 2|, the conduit 25, the condenser 25, the conduit 21, the float-operated flow-controlling device 23 and the liquid supply conduit 29 constitute a relatively high pressure refrigerant connection between the compressor I5 and the evaporator 30, while the conduit 22, the intake mumer 20, the interior of the enclosing casing I0 and the suction conduit 34 constitute a reiatively low pressure refrigerant connection between the compressor I5 and the evaporator 30.

As best shown in Fig. 2, the exhaust mutiier 2| comprises a cylindrical muilier casing formed of a series of similar casing sections of cupshaped configuration, the casing sections 35 being secured together in nested relation. A plurality of munie chambers 36 are formed in the mufer casing by end walls 31 of the casing sections 35, these munie chambers communicate with each other through restricted openings 38 formed in the end walls 31 of the casing sections 35. An enlarged inlet passage 39 is formed in the end wall 31 of the casing section 35 disposed at the upper end of the muiller casing and one Vend of the conduit 23 is securely fastened in place therein. An enlarged outlet passage 40 is formed in the cylindrical side wall of the casing section 35 disposed at the lower end of the muiiier casing and one end of the conduit 25 is securely fastened in place therein..

A diaphragm 4| normally having a concave cup-shaped configuration is secured in the open end of the casing section 35 disposed at the lower end of the muilier casing and constitutes an end wall thereof. A plate 42 is securely fastened in the open end of the casing section 35 disposed at the lower end of the muiller casing adjacent the diaphragm 4| and cooperates with the diaphragm 4| to form a relief chamber 43 therebetween. A substantially flat surface is formed on the dia- Dhragm 4| adjacent the center thereof in order to provide a relatively weak area 4|a therein. A member or pin 44 having a sharp end 44a disposed adjacent the relatively weak area 4|a in the diaphragm 4| is carried by the plate 42.v A relief passage is formed inthe plate 42 and communicates between the relief chamber 43 formed between the diaphragm 4I and the plate 42 and the interior of the enclosing casing I0.

During operation of the refrigerating machine, should the pressure in the muiile chamber 35 formed in the casing section 35 disposed at the lower end of the muiiier casing, which muilie chamber constitutes a pressure chamber, exceed a predetermined abnormally high pressure due, for example. to the failure of theiioat-operated flow-controlling device 23, the concavity of the diaphragm 4| would be abruptly changed to move the relatively weak area 4 la therein into puncturing engagement with the pin 44, as shown in Fig. 3. 'I'he abnormally high pressure condition existing in the relatively high pressure refrigerant connection between the compressor I5 and the evaporator 30 is then relieved by the flow of compressed refrigerant from the muilie chamber 36 adjacent the diaphragm 4| through the rupture m the diaphragm u, the relier chamber 43. and

the relief passage 45 in the plate 42 into the interior of the enclosing casing III.

The peripheral edge of the cup-shaped diaphragm 4| is sealed to the inner surface of the cylindrical side wall of the casing section 35 disposed at the lower end of the muilier casing, which casing section constitutes a valve casing for the pressure relief valve, and is retained in position by the plate 42 'which prevents sliding movement of the peripheral edge of the diaphragm 4|. Thus, the diaphragm 4| is capable of moving with respect to the muiiier casing only by bending outwardlyv into a substantially convex configuration and into puncturing engagement with the pin 44 upon the occurrence of a predetermined abnormally high pressure in the adJacent muiile chamber 35. Due to the normally concave configuration of the diaphragm 4|, there is only a slight bending movement thereof towards the pin 44 as the pressure in the adjacent muiiie chamber 35 increases, until the pressure in the adjacent muille chamber 35 reaches a predetermined abnormally high value moving the diaphragm 4| into an unstable position which causes the concavity thereof to be abruptly changed to move the diaphragm into puncturing engagement with the pin 44. 'Ihe substantially at surface 4|a is formed on the diaphragm 4| in alignment with the pin 44 in order to insure that the normally concave diaphragm will move into substantially uniform convex configuration, sloping from the peripheral edge towards the center thereof, and into puncturing engagement with the pin 44 when the diaphragm is moved from its unstable concave position into its convex configuration upon the occurrence of a predetermined abnormally high pressure in the adjacent muilie chamber 35. 'I'he abnormally high pressure required to move the diaphragm 4| into its unstable concave position and thence into puncturing engagement with the pin 44 is determined by the normal concavity, resiliency and thickness characteristics of the diaphragm 4|, the diaphragm being designed to be moved into its unstable concave position and thence into puncturing engagement with the pin 44 upon the occurrence of a predetermined abnormally high pressure well above the normal operating pressures existing in the relatively high pressure refrigerant connection between the compressor I5 and the evaporator 30.

The fact that the refrigerating machine is rendered substantially inoperative when the pressure relief valve is operated. upon the occurrence of a predetermined abnormally high pressure in the relatively high pressure refrigerant connection between the compressor and the evaporator. is not objectionable as I have found that abnormallyhigh pressures occur in refrigerating machines of this type very infrequently and only upon failure of some other part of the refriger ating machine requiring repair. As the refrigerating machine is hermetically sealed, it must be disassembled in any case in order to repair the part thereof which caused the abnormally high pressure condition and while the machine is disassembled a new exhaust muiiier embodying the pressure relief valve described may be readily incorporated therein.

In Fig. 4 I have shown a modified form ofthe pressure relief valve which includes a member or pin 45 formed of half-round stock secured in a circular relief passage 41 formed in the plate 42 for puncturing the diaphragm 4|, the remainder of the construction and the arrangement of the pressure relief valve being otherwise the same as that described in connection with Figs. 2 and 3.

As the pin 46 is formed of half-round stock and secured in the circular relief passage 41 formed in the plate 42, the construction is somewhat simplified as it is only'necessary to provide a single opening in the plate 42 during the course of manufacture. Furthermore, the pin 4B presents a somewhat sharper end 46a to the diaphragm 4l for rupturing the diaphragm 4l.

While I have shown a particular embodiment of my invention, I do not desire my invention to be limited to the particular construction shown and described, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire tc secure by Letters Patent of the United States is:

1. A pressure relief valve comprising a valve casing having an inlet passage and a relief passage therein, means including a diaphragm normally having a concave configuration separating said passages, thesurface of said diaphragm opposite the concave surface thereof being subjected to the pressure in said valve casing, and means including a member associated with and disposed adjacent the concave side of said diaphragm for puncturing said diaphragm to connect said passages, said diaphragm having a portion thereof so shaped that the concavity of said diaphragm abruptly changes for Amoving said diaphragm into puncturing engagement with said member upon the occurrence of a predetermined high pressure in said valve casing.

2. A pressure relief valve comprising a valve casing having an inlet passage and a relief passage therein, means including a diaphragm normally having a concave configuration separating said passages, the surface of said diaphragm opposite the concave surface thereof being subjected to the pressure in said valve casing, and means including a member associated with and disposed adjacent the concave side of said dia-A phragm for puncturing said diaphragm to connect said passages, said diaphragm having a portion thereof so shaped that the concavity of said diaphragm abruptly reverses for moving said diaphragm into puncturing engagement with said member upon the occurrence of a predetermined high pressure in said valve casing.

3, A pressure relief valve comprising a valve casing having an inlet passage and a relief passage thereln, means including a diaphragm normally having a concave configuration separating said passages, the surface of said diaphragm opposite the concave surface thereof being subjected to the pressure in said valve casing, said diaphragm having a relatively weak area, and means including a member disposed adjacent the relatively Weak area in said diaphragm on the concave side thereof for puncturing said diaphragm to connect said passages, said weak area of said diaphragm being so located that the concavity of said diaphragm abruptly changes for moving the relatively weak area in said diaphragm into puncturing engagement with said member upon the occurrence of a predetermined high pressure in said valve casing.

4. A pressure relief valve comprising a valve casing having an inlet passage and a relief passage therein, means including a diaphragm normally having a concave cup-shaped configuration separating said passages, the surface of said diaphragm opposite the concave surface thereof being subjected to the pressure in said valve casing, said diaphragm having a substantially flat surface adjacent the center thereof for providing a relatively weak area in said diaphragm, and means including a member disposed adjacent the relatively weak area in said diaphragm on the concave side thereof for puncturing said diaphragm to connect said passages, said relatively weak area causing the concavity of said diaphragm to abruptly change to move the relatively Weak area in said diaphragm into puncturing engagement with said member upon the occurrence of a predetermined high pressure in said valve casing.

5. A valve construction comprising a valve casing, means including a diaphragm having a normally concave configuration forming pressure and relief chambers in said valve casing, said pressure chamber having inlet and outlet passages therein, the surface of said diaphragm opposite the concave surface thereof being subjected to the pressure in said pressure chamber, and means including a member associated with and disposed adjacent the concave side of said diaphragm for puncturingsaid diaphragm to connect said chambers, said diaphragm having a portion thereof so shaped that the concavity of said diaphragm abruptly changes for moving said diaphragm into puncturing engagement with said member upon the occurrence of a predetermined high pressure in said pressure chamber.

HARLEY H. BIXLER. 

